Furnace



oct. 29, 1940.

A25/var /AML /lv/r www www L. c. HAMLINK FURNACE Fi'ld March 1o, 1958 Ocpzs, 1940. ,QHAMUNK 2,219,894

FURNACE Filed March 10, 1958 5 Sheets-Sheet 5 av 25 v2524 2156.5 l 24 www Oct. 29, i940. L. c. 'HAMLINK 2,219,394

FURNACE Filed March 1o. lesa' 5 sheetsfsheet 4.

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A25/var C. #AML /NK Oct. 29, 1940. C HAMUNK 2,219,894

FURNACE Filed March 10, 193s 5 Sheets-sheet 5 70 "E 69 /NVE/vrae:

Piuma oct. 29, 1940 PATENT lo1=1=1ca v FURNACE Lazenby C.'Hamlink,.Cleveland Heights, Ohio, assignor t The Gas' Machinery Company, Cleveland, Ohio, a corporation of Ohio Application March 10, 1938, Serial No. 195,075 1o claims.' (ol. 26e-5) My invention relates to furnaces and particularly to annealing and other heat-treating fur- Y naces. The objects of the invention are to provide apparatus of this character which can be a economically made and assembled, which is efficient in operation, and the heating elements of which will be extremely resistant to deterioration during operation. A primary object of the invention is to provide new and improved heating tubes l0 for annealing and other heat-treating furnaces, and new and improved assemblies of such tubes and the other necessary elements of such furnaces. i

The annexed drawings and the following description set forth in detail certain means illustrating my improved furnace structures, such means constituting only a few of the various forms in which the principles of the improved furnaces may be embodiedt 2o In said annexed drawings:

Figure 1 is a vertical longitudinal section of an annealing furnace embodying one form of my invention, the section being taken in the plane indicated by the line l-i, Figures 4 and 5, the

25` showing being that of a rectangular furnace in y which a removable outer cover is utilized and in which heating gases are fired at different vertically-aligned levels, two series of improved refractory heating tubes being incorporated in the 90 furnace adjacently interior of opposed side walls,

said tubes being secured at the center, the assembly being such that the tubes can expand at both ends;

Figure 2 is a fragmentary vertical longitudinal 35 section of a, form of joint between the adjacent ends'of contiguous sections of aheating tube, different than the form of such joint included in Figure 1 in that the tube shown in Figure 2 can expand at the joint, a modified form of tube- 40 supporting structure also being shown in this figure, the section being taken in the plane indicated by the line 2-2,Figure 3;

Figure 3 is a fragmentary vertical transverse longitudinal section of the furnace assembly as shown at the right hand end of Figure l, the section being taken'in the plane indicated by the line '1 -1, Figures 4 and 8;

Figure 8 is a fragmentary enlarged vertical transverse section, takenin the plane indicated y by the line 8 8, Figures 4 and 7;

Figure 9 is a fragmentaryenlarged vertical longitudinal section showing the nature of the central joint between adjacent ends of contiguous sections of my new and improved heatin tube shown in Figures 1, and 4-8;

Figure 10 is a view similar to Figure 9, but showing a joint between contiguous sections of the heating tube, other than the central joint;

Figure 11 is a view similar to Figure 10, butv showing a modification of the joint between the v adjacent ends of contiguous sections of the heating tube;

Figure 12 is a broken and fragmentary verti- 20 cal longitudinal section of an annealing furnace embodying va modified form of my invention in that the cooperative arrangement of the heating tube assembly with the furnace walls is different from that shown in Figure 1, 'the figure also 25 illustrating a formof structure in which the expansion of the heating tubes is provided for entirely at one end of the tubes;

Figure 13 is a fragmentary vertical longitudinal section, upon an enlarged scale, of the structure shown in Figure I2, the section being' taken in the plane indicated by the line l3-I3, Figure 14;

Figure 14 is a fragmentary vertical transverse section, taken in the planes indicated by the line I4-|4, Figure 13;

Figure 15 is a fragmentary horizontal longitudinal section, taken in the plane indicated by the line I5-I5, Figure 13;

- Figure 16 is a fragmentary vertical longitudinal 40 section through that endlof the furnace shown in Figures 12 and 13 opposite the end thereof which is shown in` vFigure 13;

Figure 1'7 is a fragmentary vertical longitudinal section, similar to Figure 13, but on a smaller scale, of a further modified form of annealing furnace in which expansion of my 'improved heating tubes is provided for entirely at one end of the furnace, the section being taken in the plane indicated by the line i'l-I'l, Figure 18; and 50 Figure 18 is afragmentary vertical transverse section, taken in the plane indicated by the line l8--I8, Figure 17.

Referring to the annexed drawings in which the same parts are indicated by the same respeco5 tive numbers in the several views, and first particularly referringjto Figures l, 4, 5,f` 6,7, 8, 9,

and 10, a form of` my improved furnace construction is exemplified in a rectangular annealing furnace having a removable outer cover or hood with refractory end walls I, side wallsl2, Vand-an 'arched brick roof portion 3 topped by refractory insulating material I5. To the endlwalls are secured exterior plates 4 tojwhose .exterior faces-v are secured spaced vertical I-beams 5. Intermediate adjacent I-beams 5 are pairs of opposed horizontal channel sections forming box' girde'rs- 6, `the outer iianges ofthe channel sections being' secured together by plates 1 which are welded to said flanges and the outer flanges of the I-beams 5. The remainder of the reinforcing exterior side 'structure comprises longitudinal plates 4' secured to the exterior faces of the side walls 2, to the exterior faces of which plates 4' .vertical I-beams 5' are secured; also intermediate horizontal pairs of opposed channels whose outer fianges are welded together by'plates 1"I to form box gir-ders. 8'. Exterior longitudinal channels 9 and transverse channels are secured to the top ends of the vertical end I-b'eams 5 and the vertical side I-beams 5'. Secured to the top of' the end I-beams -5 and upon a plate 38 mounted upon the top of the insulating material I8 are intermediate longitudinal I-beams l3 braced by cross I-beams |0,'these I-beams 8 and I0 being ex-4 tended across the roof of the furnace. To provide lifting means |2'whereby the aforedescribed hood may be positioned on or removed from the furnace base, there are secured to the top of the roof I -beam's I 0 a pair of spaced longitudinal and upwardly-extended `Ibeams I3 which are secured together. by a bar I4 whose bottom edge is somewhat spaced `from the I-beams II) whereby to provide a hook or grab slot I5. -To the base of the' hood structure is secured a peripheral plate -I1 vforming a supporting and wear member for the seating o f the hood upon the furnace base, this plate |1 having a depending flange I8 which dips into a base seal, hereinafter described,

.22, into which sand the aforementioned `depending flange I8 of -the hoo'd dips. Secured tothe lower face of the base plate 28 are longitudinal I-beams 23 and transverse I-beams 24. I provide meansfor properly positioning the hood upon the furnace base I8, thesame consisting of two pairs of relatively vertically disposed plates 25, Figures 4 and 5, extended from one side of each of 'the outside I-beams 23v and formed with a socket to hold guide posts 28,- which guide posts are adapted to register with spool-shaped members 21 'secured to the base plate |1, when the hood is movv y ing downwardly in proper registering position.

Incorporated in the described hood structure are refractory tubes 3| for heating the work 50 in the furnace chamber 28, this work 50 being piled upon a suitable hearthplate 29 secured to the top of the refractory furnace base I9, the work 50 preferably being coveredby all. inner cover 5| during the heating and subsequent cooling operations. The heating tubes 3| are disposed in two longitudinal .series extended along the side walls 2-of the hood and adjacently interiorly of said side walls, .each series comprising a plurality 'of verticallyaligned tubes 3|, and each tube comprising a plurality of sections whose adjacent ends are jointed by means hereinafter described. These refractory heating tubes 3| are slidably mounted upon the top surfaces of spaced horizontal brackets 32 whose outer ends are in- Walls 2- and whose inner ends project inwardly of saidside walls into the furnace chamber 28, as clearly shown in Figure 6. Referring particularly to Figure' 10, itwill be noted that the joint between the adjacent 'ends ofeach two contiguous corporated with and mounted in the hood side tube sections 3| is covered by a collar 35 mounted 1 on a bracket 32 and having an opening slightly relatively to the supportingfbrackets 32, so that any expansion .of the heating tube 3| during the heating operation can be accommodated at the end hood walls I as as will be hereinafter fully described. However, I vfasten the heating tubes 3| at the center joint and for this purpose I provide a special center bracket or support 32', Figure 9, which has upwardly-extended end anges 322 serving to restrain the tube sections at this central joint against longitudinal movement, since the central joint collar 35', which is of elongated formation at its lower end, is confined in the recess 323 formed between the two end flanges 322 of the central support 32'.

Except at the top and bottom, the hood end lwalls l, adjacent the ends of the heating tubes 3 I, do not extend entirely across the ends of the hood completely to fill the spaces between the ends of the'side lwalls 2 but terminate short of the ends of said side walls 2. Refractory supporting blocks 46, Figures 4 and 7, for the ends of the heating tubes 3| are mounted between the adjacent vertical surfaces of the end walls and the side walls 2 and the adjacent horizontal surfractory tubes 3|,'these recesses 31 being somewhat larger in diameter than the diameter of the heating tubes 3|. The blocks 46 are also formed with vertically aligned openings 38, the upper opening 38 having an opentop and the bottom opening having a closed end, the openings 38 intersecting the recesses 31, so that sand 39 can be poured into the o pen top of the upper opening 38 to illl all the openings 38, which sand 'also fills Ain between the walls of theA recesses 31 and the exteriorA surfaces of the heating tubes 3|, all as `shown in Figures 7 and 8. For facilitating the application of the sand 39, an adjacent corner of the top portion of the-end wall is cut oil', as inf dicated by the number 38', Figure 7.

The blocks 46, at one end of the removable hood shown in Figure 7. A gas riser 40' is also provided at the left hand end of the heating tube structure, which riser 40 vertically connects adjacent tubes of two pairs of heating tubes 3|. In other words, each right hand riser 40 connects the open ends of the two tubes of each pair oi' tubes, and the left hand riser 40 connects the open ends of one of each of two pairs of tubes. These two adjacent tubes can expand in the gas riser 43'. In .the accompanying drawings, I show four vertically-aligned heating tubes 3|, for purposes of illustration. The other two heating tubes 3| expand at their left-hand ends in vertical chambers 33 formed in two of the left hand blocks 43 and vertically-aligned with the gas riser 40'. Intersecting the risers 4D on the right hand side are openings 4| in the upper of each pair of blocks 46, and intersecting the top of the-riser 40' on the left hand and also the lower chamber 33 on the left hand are similar openings 4|, aligned communicating openings 41' being formed in the insulating plates 41 and the end plates4, whereby heating gases can be fired into the refractory tubes 3i from burners 42. In the form of apparatus described, the burners 42 atthe left hand end'of the apparatus, Figure 1, re into the lower tubes of the two pairs of heating tubes 3| and the burners 42 at the right hand end of the furnace are booster burners which fire into the upper tubes of the two pairs of refractory tubes 3|, the lower tube having no outlet,but communicating with the upper tube of its pair through a riser 40. The upper tube of the lower pair of tubes 3| has an outlet flue 43 passed through one of the left hand end blocks 46, this flue 43 being provided with an ejector 44. The upper tube of the upper pair of tubes 3| also has an outlet flue 43 passed through a left hand block 45. If it is desired that the same heating gases pass through the entire vertical series of tubes 3|, the lower ue 43 is covered by a cap 4 5 and the partially spent gases pass at the left hand end of the furnace from the upper of the lower pair of heating tubes 3| to the lower of the upper pair of heating tubes by means of i the left hand riser 43', so that in that case the upper burner 42 on the left hand end of Figure 1 acts as a booster burner as well as the burners 42 at the right hand end of Figure 1 and the outlet for all the products of combustion is the upper flue 43 also passed through one of the left hand blocks 46.

To insure non-leakage oi' outside atmosphere into the heatingvcompartment within the inner cover 5I, sand 43, Figure 6, ispiled upon the refractory base I9 exteriorly o'f the bottom edge of the cover BI.

Referring to Figure 11, a modified form of face joint between the ends `of contiguous tube sections is utilized, consisting of an interlockingtongue and groove 62 in addition to the mere abutting of such end faces, such as is shown in Figure 10.

Referring to Figures 2 and 3, I illustrate a form of support for the heating tubes 3l and joint means for adjacent ends of contiguous sections of the tubes which provides for expansion'between each two contiguous sections of the heating tubes. In this form of structure, the tubes are supported by tile forming a chambered structure, the tile having abutting end faces formed with interlocked tongues and grooves 54..the adjacent ends of contiguous tube sections being spaced within the tile 5,3 so as to provide an expansion space 55. Recesses 53 in the tile 53`through which the tube section'ends extend are somewhat larger than the diameter of the tube and the collar 51 which covers the adjacent ends of contiguous tube sections is also somewhat larger -in diameter, as illustr'ated by the recess B8, than the diameter of the tube section. Thel chamber within the tile structure is lled with sand 63 and this' sand sifts into the recesses 58 and |53 whereby leakage of gas is substantially entirely eliminated while permitting necessary expansion between adjacent sections of the heating tube structure.

The assembly of. elements forming the annealing furnace which has been described lends itself with particularly satisfactory results to the use of heating tubes made of refractory material. The nature of the incorporation of the heating ,tubes in the removable hood, and the relation'of the heating tubes to the heating chamber and the ywork positioned therein under the inner cover.

render 'efficiently available the emissivity and thermo-conductive factors of the refractory heating tubes, as well` as rendering available the mechanical strength thereof, at the same time effecting highly satisfactory and economical heating of the work by radiation from the heating tubes. The 'assembly allows for the necessary ex,- pansion of the refractory heating tubes without the subjecting of the latter to undue strains, and the arrangement of the tubes in vertically-aligned series, combined with the method of firing into, and venting from, the same, provide uniform heating temperatures throughout the work chamber. Leakage of' heating gases from the heating tubes, and disturbance of the desired atmospheric conditions within the inner cover 5|, are effectually prevented. These conditions under the cover 3| are variable for different purposes, all as well understood in the art, and the obtaining of which, whether neutral, oxidizing or de-oxidizing, are standard practices also well understood in the art, and a showing of which has not been included in the instant specification or accompanying drawings.

The operation of the described furnace is the one usually incident to that of an annealing furnace having a removable hood. Briefly, it conthe venting of products of combustion being through the two ues 43, Figure 1, or, if desired. the lower ue 43 is covered by the cap 45 and the entire' venting of products of combustion takes' place through the upper `fiue 43.

Referring to the type of furnace shown in Figures 12-16, refractory heating tubes 6I are permitted to expand at one end only. As shown in these figures, for the purpose of illustration, the expansion takes place at the right hand end of the tube. I'he left hand end is secured in blocks 4|;2 of a furnace end. wall by cement 02, Figure 16. Blocks 46' at the right hand 'end wall l are formed with holes 63 therethrough somewhat larger in diameter than the diameter of the tube 6| and the end of the tube'i-s passed through this hole 63 and extends outwardly from the blocks 46', Figure 13. An angle 64 is secured to the exterior face of the lower part of the wall plate 4 and secured to an extended end portion of the base plate I1 is a reversed angle 65 which forms with the angle 64 a box girder upon which is mounted a vertical metal plate 66 through enlarged holes B3' of which also extend the tubes 6I, the plate 6B being positioned at such a dls' tance exteriorly of the wall plate 4 as to form an intervening vertical space 61.Which is open atY the top and is filled with sand 68. This sand also sifts into the annular recesses between the exterior of the refractory tube 16! and the adjacent surfaces of the blocks 46' and plate 66. Secured to collars 69' which in turn are secured to the outer face of the vertical plate 66, and around the several holes 631 of saidplate 66, are outwardly-extended hoods 69 into. which the ends `of the refractory heating tubes 6I extend and within which are provided expansion spaces 10 for the respective tubes 6I, as indicated by dotand-dash lines, Figure 13, alternate hoods 69 having openings 692 intersected by burners 1I which fire into vertically alternate refractory tubes 6I. As shown in FigureslZ and 13, the

burners 1| fire into the bottom tube 6| and the third from the bottom, the second and fourth tubes from the 'bottom discharging into ues 12 supported on Avertically alternate hoods 469 and communicating with the-chambers thereof. -The heating medium passes at the left hand end of the furnace from the bottom tube 6| to the next higher tube, or from the tube which is the third from the bottom to the next higher tube, by means of risers 13 formed in the left hand blocks In the form of furnace shown in Figures 12-16, each pair of heating tubes 6l is ilred at one 'end only, the firing, and the venting of products of combustion, all being effected at one end of the furnace. .l l i A modification ofthe form of furnace shown in lFigures 12-16 is illustrated in Figures 17 and 18 in thatthe furnace end walll and the blocks 463 thereof are `formed with a vertical opening 15 which has an outwardly-bent upper section in which is mounted a metal funnel 15 which intersects and extendsY outwardly of the furnace wall plate 49 and thus serves as means for the feeding of sand 16 into the opening 15, which sand also sifts into the annular sections of enlarged tube-accommodating holes 11 formed in the blocks 463 of the furnace wall I. In this form of furnace the ends of the refractory tubes 6| also project outwardly from the furnace end wall I and in the case of the lower tube and the tube third from the bottom receiveheatlng gases from burners 19, and in .the case of the alternate tubes discharge into flues 8|, the burners 19 being mounted in outwardly-extended angular portions 18 of a Wall plate 49 and the flues 8| having end collars 80 which aremounted upon tubes, which discharges into the flue -8I, the

expansion is accommodated exteriorly of the furnace. the flue Il moving with the expanding a whereby to obtain uniform heating or such lo calized heating as may be desired during the heating operation or. certain stages thereof.

What I claim is:

1. A furnace includinga casing having a base and a removable cover cooperating therewith to form a heating chamber, vertical series of refractory heating tubes so mounted in and supported by said cover upon opposed sides of the latter as to provide for expansion of the tubes,

vertical passages formed in the cover wall respectively With which'the several tubes of all the tubes of the several banks of tubes communicate, a bank of tubes comprising at least two tubes, burners ring respectively into at least one of said tubes of each of the several banks of tubes,- at least one burner Aring into the passage communicating vwith a bank of tubes, and a flue from each' bank of means for exhausting' products of combustionfrom the heating element, and spaced supports for the heating .element mounted in they furnace wall and slidably engaging and supporting said jointgsealing means.

3. Ina furnace, heating means and means for supportingthe heatingmeans so as to permit expansion of the latter, comprising a furnace wall.,

a heating element consisting of a plurality of communicating tube units of refractory material, including tube units substantially central of the length of the heating' element, means sealing the joints between Vadjacent units, means for applying heat interiorly of the heating element, means for exhausting products of combustion from the heating element, the furnace wall being formedwith expansion vchambers into which the ends of the heating element extend, a substantially central support for the heating element mounted in the furnace wall and to which said central-tube unitsare fixed, and other spaced supports for the heating element mounted in the furnace wall and slidably engaging and supporting said joint-` sealing means.v v

4. In afurnace, heating, means and means for supporting the heating means so as to permit expansion of the'latter, comprising a furnace Wall,

a heating element movably mounted. in said wallv and consisting of la plurality' of communicating tube units of refractory material, collars covering sok the joints b etween adjacent units and means for sealing the collars, means for applying heat interiorly o f the heating element, means for ex, haustingA products of combustion from the heat: ing element, and spaced, supports lfor theheating element mounted'in the furnace wall and slidably engaging and supporting said collars.

5. A furnace including a casingv having a -base' and a' removable cover,l cooperating therewith to form aheating chamber, a'vertical series of refractory heating tubes so mounted .in and supported by said cover as to provide for expansion of the tubes, vertical passages formed in the cover wall respectively with which Aall the tubes of the several banks of tubes communicate, abank of tubes comprising at least two tubes, burners firing respectively into at least one of said tubes of each of the several banks of tubes, and a flue from each bank of tubes.

6. A furnace including a casing having a base and a removable cover cooperating therewith to form a heating chamber, vertical series of refractory heating tubes mounted in and supported by said cover upon opposite sides of the latter, said heating tubes being freely extended at their ends into the cover wallso as to provide for the expansion of the tubes, a vertical passage in said wall for each pair of tubes, the latter communicating at one -end with said passage, vertical passages in the cover wall with which the other ends of the tubes communicate to provide communication between adjacent'pairs of tubes, burners firing through the cover wall into the ends of the respective tubes, and flues extended outwardly of the cover wall and communicating with an end of the respective pairs of tubes.

7. A furnace including a casing having a base and a-removable cover cooperating therewith to form a heating chamber, vertical series of refractory heating tubes mounted in and supported by said cover upon opposite sides of the latter, said heating tubes being freely extended at their ends into oppositesides of the cover wall so as to provide for the expansion of the tubes, vertical passages in one of said wall sides, a passage for each pair o tubes, the latter communicating at one end with said passage, vertical passages in the opposite side of the cover wall, the other ends of one tube of each adjacent pairs of tubes com-v municating with one of saidv last-mentioned passages, burners firing through said opposite side of the cover wall into the end of one tube of the respective pairs of tubes, burners firing through said one wall side into an end of the other tube of the respective pairs of tubes, ues from the respective pairs of tubes communicating each with a vertical passage in said fopposite side of the cover wall, and means for controlling the passage of products of combustion as between said flues and said last-mentioned vertical passages.

. 8. A furnace including a casing having a base and a removable cover cooperating therewith to form a heating chamber, a vertical series of refractory heating tubes movably mounted in and supported by said cover, vertical passages formed in the cover wall with which respectively both tubes of the several banksof two tubes communicate, means for sealing and fastening an end of each tube in the cover wall adjacent said passages, burners respectively ring into the opposite end of a tube of the several banks of tubes, supportsfor the burners secured to the cover wall and having expansion chambers into which the ends of the cooperating tubes extend, ues for the respective banks of tubes, and supports for the flues secured to the cover wall and having expansion chambers into which the ends of their cooperating tubes extend.

9. A furnace including a casing havinga base,4

a wall, and a roof, and forming a heating chamber, a vertical series of refractory heating tubes disposed in said 'chamber and movably mountedh at their endsv in said wall, burner housings secured to said wall and forming expansion chambers into which an end of a tube of the several pairs of tubes extends, burners firing into said housings, respectively, ues secured to said wall and' having housing portions forming expansion chambers into which an end of the other tube of the wall, spaced from and forming sand chambers exteriorly of the latter, the ends of the tubes being extended through'said plates, burner housings forming tube expansion chambers secured to said plates and into which one end of one of each of the respective pairs of tubes extends, burners i-lring into said end of said tubes through said housings, flues mounted upon an end of the other tube of each pair of tubes, passages in said wall with which the tubes of each pairof tubes communicate, and a plurality of spaced tube supports extended inwardly of said wall and slidably engaging the tubes.

LAZENBY C. HAMLINK. 

